You don’t need a four-wheel drive to reach the Onizuka International Astronomy Visitor Center, named for Hawai‘i’s astronaut who died in the Challenger explosion. The center is open 9 AM–9 PM daily. After dark, there are free stargazing programs. Check about stargazing opportunities well in advance of your visit. Acclimate to the altitude here (elevation 9200 feet) and learn about the mountain’s geology and its significance to native Hawaiian culture. Spend about two hours exploring the area before proceeding to the summit.
You can drive to the summit, weather permitting if you have your own four-wheel drive (an AWD doesn’t count). Why 4WD? The air is too thin to adequately cool a vehicle’s brakes upon descent. It’s about 8 miles, ascends another 5,000 feet, and takes about 45 minutes. Plan to spend about three hours on the adventure. Follow the serious rules of the road. Along the way, the topography morphs into a moonlike landscape. It’s no wonder the Apollo astronauts trained here. Breathe deeply (you probably won’t be able not to!) to get enough oxygen.
Thirteen telescopes, operated by NASA and countries from around the world, crown the summit. Since this rarefied atmosphere is practically completely free from clouds, dust, and light pollution, and since it sits so close to the equator, almost 90 percent of the stars in the universe are visible from here. It gives a whole new meaning and dimension to the notion of stargazing.
Atop the summit, you can visit the Subaru Telescope for a 30-minute tour. Book well in advance.
You can visit a model of the world’s largest telescope, the Keck Telescope, operated by the University of California and the California Institute of Technology. You also get an astonishing impression of Mauna Kea’s neighbor, Mauna Loa, and Maui’s Mount Haleakala. It’s an impression that will remain indelibly imprinted on your psyche for years to come.
Although you can’t see it from Summit Road, the glacial Lake Waiau sits at 13,000 feet. It’s only half a mile off Saddle Road and quite worth stopping; ask for directions from the visitor’s center.
For a deeper dive into the cosmos vis-a-vis Hawaiʻi, visit the Institute for Astronomy (University of Hawaiʻi ).
*THAT SAID, most people will visit on a commercial tour. I’ve always come with Hawaiʻi Forest & Trail.